1. Field of the Invention
The present invention relates to an ultrasonic welding apparatus for welding a welding workpiece by applying the ultrasonic wave, and a method for producing a welded product in which a plurality of welding workpieces are welded to one another.
2. Description of the Related Art
An apparatus for producing a two-way opening filing case is disclosed in Japanese Patent Application Laid-open No. 10-278470. An OPP film (oriented polypropylene), which is wound around a film roll, is doubly folded in the widthwise direction. The OPP film is interposed between a receiver and a welding horn (an ultrasonic horn) which extends over the entire width of the folded OPP film. In the apparatus for producing the two-way opening filing case, the folded OPP film can be ultrasonically welded at the welding portion which extends along a straight line over the entire width thereof.
However, the apparatus for producing the two-way opening filing case described in Japanese Patent Application Laid-open No. 10-278470 has the welding portion which extends along the straight line in the widthwise direction of the OPP film as described above. Therefore, it is impossible to weld any OPP film in any area having a shape different from that of the welding portion. In order to perform the welding of such a type, it is necessary to exchange the welding horn with any distinct one. That is, it is necessary to prepare exclusive welding horns depending on the shapes of areas to be subjected to the welding.